For various reasons well known to persons skilled in the art, known core members of paperboard material are not particularly satisfactory for use with modern day paper making equipment and printing presses. Such known core members tend to be weak and unstable and present problems because of external surface discontinuities produced by metal end reinforcements.
Tubular core assemblies which have a hollow cylindrical core member of paperboard material and an annular end member of plastic material within each opposite end portion of the core member are known, see for example U.S. Pat. No. 6,193,186 issued Feb. 27, 2001, the contents of which are hereby incorporated herein by reference.
It has been realized that it would be advantageous to make the core member of harder and more stable material such as metal or plastic material. However, merely making the core member of known tubular core assemblies of metal or plastic material instead of paperboard material does not provide a satisfactory solution, because such a metal or plastic core member would be unduly heavy since its wall thickness is dictated by the design thickness of the paperboard tubular core assemblies in common usage in mill gang winding operations.
It is therefore an object of the present invention to provide a tubular core assembly with a metal or plastic core member and appropriate end members which does not suffer from the problem mentioned above.